Represents a construct that can be annotated.
A construct is either an element or a type. Annotations on an element
are on a declaration, whereas annotations on a type are on
a specific use of a type name.
The terms directly present, present,
indirectly present, and associated are used
throughout this interface to describe precisely which annotations
are returned by the methods defined herein.

In the definitions below, an annotation A has an
annotation type AT. If AT is a repeatable annotation
type, the type of the containing annotation is ATC.

Annotation A is directly present on a construct
C if either:

A is explicitly or implicitly declared as applying to
the source code representation of C.

Typically, if exactly one annotation of type AT appears in
the source code of representation of C, then A is
explicitly declared as applying to C.
If there are multiple annotations of type AT present on
C, then if AT is repeatable annotation type, an
annotation of type ATC is implicitly declared on C.

A representation of A appears in the executable output
for C, such as the RuntimeVisibleAnnotations or
RuntimeVisibleParameterAnnotations attributes of a class
file.

An annotation A is present on a
construct C if either:

A is directly present on C.

No annotation of type AT is directly present on
C, and C is a class and AT is inheritable
and A is present on the superclass of C.

An annotation A is indirectly present on a construct
C if both:

AT is a repeatable annotation type with a containing
annotation type ATC.

An annotation of type ATC is directly present on
C and A is an annotation included in the result of
calling the value method of the directly present annotation
of type ATC.

An annotation A is associated with a construct
C if either:

A is directly or indirectly present on C.

No annotation of type AT is directly or indirectly
present on C, and C is a class, and AT is
inheritable, and A is associated with the superclass of
C.

getAnnotation

Returns this construct's annotation of the specified type if
such an annotation is present, else null.

The annotation returned by this method could contain an element
whose value is of type Class.
This value cannot be returned directly: information necessary to
locate and load a class (such as the class loader to use) is
not available, and the class might not be loadable at all.
Attempting to read a Class object by invoking the relevant
method on the returned annotation
will result in a MirroredTypeException,
from which the corresponding TypeMirror may be extracted.
Similarly, attempting to read a Class[]-valued element
will result in a MirroredTypesException.

Note: This method is unlike others in this and related
interfaces. It operates on runtime reflective information —
representations of annotation types currently loaded into the
VM — rather than on the representations defined by and used
throughout these interfaces. Consequently, calling methods on
the returned annotation object can throw many of the exceptions
that can be thrown when calling methods on an annotation object
returned by core reflection. This method is intended for
callers that are written to operate on a known, fixed set of
annotation types.

Type Parameters:

A - the annotation type

Parameters:

annotationType - the Class object corresponding to
the annotation type

Returns:

this construct's annotation for the specified
annotation type if present, else null

getAnnotationsByType

Returns annotations that are associated with this construct.
If there are no annotations associated with this construct, the
return value is an array of length 0.
The order of annotations which are directly or indirectly
present on a construct C is computed as if indirectly present
annotations on C are directly present on C in place of their
container annotation, in the order in which they appear in the
value element of the container annotation.
The difference between this method and getAnnotation(Class)
is that this method detects if its argument is a repeatable
annotation type, and if so, attempts to find one or more
annotations of that type by "looking through" a container annotation.

The annotations returned by this method could contain an element
whose value is of type Class.
This value cannot be returned directly: information necessary to
locate and load a class (such as the class loader to use) is
not available, and the class might not be loadable at all.
Attempting to read a Class object by invoking the relevant
method on the returned annotation
will result in a MirroredTypeException,
from which the corresponding TypeMirror may be extracted.
Similarly, attempting to read a Class[]-valued element
will result in a MirroredTypesException.

Note: This method is unlike others in this and related
interfaces. It operates on runtime reflective information —
representations of annotation types currently loaded into the
VM — rather than on the representations defined by and used
throughout these interfaces. Consequently, calling methods on
the returned annotation object can throw many of the exceptions
that can be thrown when calling methods on an annotation object
returned by core reflection. This method is intended for
callers that are written to operate on a known, fixed set of
annotation types.

Type Parameters:

A - the annotation type

Parameters:

annotationType - the Class object corresponding to
the annotation type

Returns:

this construct's annotations for the specified annotation
type if present on this construct, else an empty array